Heating assembly for a thermostatic valve and corresponding production method, and a thermostatic valve comprising such an assembly

Abstract

This heating assembly comprises a thermally conductive tube ( 42 ), to be immersed in a thermally expandable material of a thermostatic element of a valve, an electric heating resistor disposed inside the tube and from which there extend electrically conductive wires ( 62 ), and a unitary housing ( 1 ) made from plastic, through which the fluid to be regulated flows via the valve, and which is secured by over-molding of a longitudinal end portion ( 44 ) of the tube. In order to make the molding of the over-molded housing simple and inexpensive to carry out, while being easy to adapt to various geometric forms of the heating assembly, the invention proposes that, before the housing is molded, a reinforcement ( 7 ) for supporting the wires outside the tube, which is separate from the housing, and to which the housing is secured by over-molding, can be securely mounted on the end portion of the tube and supports the wires outside the tube, said wires being externally mounted on the reinforcement, and, when the housing is being molded, keeps the wires in place while the plastic material of the housing coats these wires, the reinforcement and the end portion of the tube.

The invention claimed is: 
     
       1. A heating assembly for a fluid control thermostatic valve, comprising:
 a tube, which is thermally conductive, which has a longitudinal central axis and which is configured to be plunged in a thermally expandable material of a thermostatic element of the valve, the tube having a terminal longitudinal part which includes an outwardly flared end, 
 an electric heating resistance, which is positioned inside the tube and from which electrically conducting wires extend outside the tube, 
 a single-piece housing, which is made from a plastic material, which is configured to permit a fluid to flow therethrough and which is secured by overmolding to the terminal longitudinal part of the tube, and 
 a framework for supporting and keeping in place the conductive wires outside the tube, the framework being separate from the housing and fixedly attached directly to the terminal longitudinal part of the tube, 
 wherein the framework includes a first end part which turns toward the tube and which is elongated in a transverse direction with respect to the central axis, said first end part surrounding and being fastened to the outwardly flared end of the terminal longitudinal part of the tube, and 
 wherein the framework, the conductive wires outside the tube and the terminal longitudinal part of the tube are jointly coated with the plastic material of the housing during molding of the housing. 
 
     
     
       2. The heating assembly according to  claim 1 , wherein the framework is made in a single piece. 
     
     
       3. The heating element according to  claim 1 , wherein the framework further includes a second end part, which turns opposite the tube, and a running part, which extends between the first end part and the second end part of the framework. 
     
     
       4. The heating assembly according to  claim 3 , wherein, between the second end part and the running part of the framework, the framework comprises a flexible zone configured to be deformed so as to adjust the relative positioning between the second end part and the rest of the framework before molding of the housing. 
     
     
       5. The heating assembly according to  claim 3 , wherein the second end part of the framework has through holes configured to complementarily receive electrical connecting studs that are respectively electrically connected to the conductive wires before molding of the housing. 
     
     
       6. The heating assembly according to  claim 3 , wherein the running part of the framework delimits a longitudinal trough which is configured to receive the conductive wires outside the tube, in which the wires run lengthwise between the first and second end parts of the framework and which is provided with a retainer configured to keep in place the conductive wires outside the tube before molding of the housing. 
     
     
       7. The heating assembly according to  claim 1 , wherein the heating assembly further comprises a single sealing gasket which is both inserted radially between the housing and the tube and arranged axially against the first end part of the framework. 
     
     
       8. A fluid control thermostatic valve, comprising:
 a heating assembly according to  claim 1 , 
 a valve housing consisting at least partially of the housing of the heating assembly, 
 a closure member configured to regulate the flow of a fluid through the valve housing, and 
 a thermostatic element, comprising a stationary part fixedly connected to the valve housing, and a moving part that bears the closure member and is movable relative to the stationary part under the expansion action of a thermally expanding material in which the tube of the heating assembly is plunged. 
 
     
     
       9. The heating assembly according to  claim 1 , wherein the first end part of the framework is fastened to the outwardly flared end of the terminal longitudinal part of the tube by cooperating through complementary shapes. 
     
     
       10. The heating assembly according to  claim 4 , wherein the flexible zone of the framework is thinner with respect to the rest of the framework. 
     
     
       11. The heating assembly according to  claim 7 , wherein the sealing gasket is an O-ring seal. 
     
     
       12. The heating assembly according to  claim 7 , wherein the sealing gasket is a four-lobed seal. 
     
     
       13. A heating assembly for a fluid control thermostatic valve, comprising:
 a tube, which is thermally conductive, which has a longitudinal central axis and which is configured to be plunged in a thermally expandable material of a thermostatic element of the valve, 
 an electric heating resistance, which is positioned inside the tube and from which electrically conducting wires extend outside the tube, 
 a single-piece housing, which is made from a plastic material, which is configured to permit a fluid to flow therethrough and which is secured by overmolding to a terminal longitudinal part of the tube, and 
 a framework for supporting and keeping in place the conductive wires outside the tube, the framework being separate from the housing and fixedly attached directly to the terminal longitudinal part of the tube, 
 wherein the framework includes a first end part, which turns toward the tube and which is elongated in a transverse direction with respect to the central axis, a second end part, which turns opposite the tube, and a running part, which extends between the first end part and the second end part of the framework, 
 wherein the framework, the conductive wires outside the tube and the terminal longitudinal part of the tube are jointly coated with the plastic material of the housing during molding of the housing, and 
 wherein, between the second end part and the running part of the framework, the framework comprises a flexible zone configured to be deformed so as to adjust the relative positioning between the second end part and the rest of the framework before molding of the housing. 
 
     
     
       14. The heating assembly according to  claim 13 , wherein the flexible zone of the framework is thinner with respect to the rest of the framework. 
     
     
       15. The heating assembly according to  claim 13 , wherein the framework is made in a single piece. 
     
     
       16. A fluid control thermostatic valve, comprising:
 a heating assembly according to  claim 13 , 
 a valve housing consisting at least partially of the housing of the heating assembly, 
 a closure member configured to regulate the flow of a fluid through the valve housing, and 
 a thermostatic element, comprising a stationary part fixedly connected to the valve housing, and a moving part that bears the closure member and is movable relative to the stationary part under the expansion action of a thermally expanding material in which the tube of the heating assembly is plunged. 
 
     
     
       17. A heating assembly for a fluid control thermostatic valve, comprising:
 a tube, which is thermally conductive, which has a longitudinal central axis and which is configured to be plunged in a thermally expandable material of a thermostatic element of the valve, 
 an electric heating resistance, which is positioned inside the tube and from which electrically conducting wires extend outside the tube, 
 a single-piece housing, which is made from a plastic material, which is configured to permit a fluid to flow therethrough and which is secured by overmolding to a terminal longitudinal part of the tube, and 
 a framework for supporting and keeping in place the conductive wires outside the tube, the framework being separate from the housing and fixedly attached directly to the terminal longitudinal part of the tube, 
 wherein the framework includes a first end part, which turns toward the tube and which is elongated in a transverse direction with respect to the central axis, and a second end part, which turns opposite the tube, 
 wherein the framework, the conductive wires outside the tube and the terminal longitudinal part of the tube are jointly coated with the plastic material of the housing during molding of the housing, and 
 wherein the second end part of the framework has through holes configured to complementarily receive electrical connecting studs that are respectively electrically connected to the conductive wires before molding of the housing. 
 
     
     
       18. The heating assembly according to  claim 17 , wherein the framework is made in a single piece. 
     
     
       19. A fluid control thermostatic valve, comprising:
 a heating assembly according to  claim 17 , 
 a valve housing consisting at least partially of the housing of the heating assembly, 
 a closure member configured to regulate the flow of a fluid through the valve housing, and 
 a thermostatic element, comprising a stationary part fixedly connected to the valve housing, and a moving part that bears the closure member and is movable relative to the stationary part under the expansion action of a thermally expanding material in which the tube of the heating assembly is plunged.